A sponge is a tool, implement, utensil or cleaning aid consisting of porous material. Sponges are used for cleaning impervious surfaces. They are especially good absorbers of water and water-based solutions.
Sponges are commonly manufactured from cellulose wood fibres, or foamed plastic polymers. Some natural sponges are still sold for the same purpose, although most natural sponges are now used either as body/facial sponges (bath sponges) or as decorating tools used for sponge painting.
There are three other categories of available synthetic sponges, low-density polyether (known as the rainbow packs of non-absorbent sponges), PVA (very dense, highly absorbent material with no visible pores) and polyester.
Polyester sponges are also sub-divided into a variety of types, some being reticulated (artificially broken-in) for ease of use. Other types are double-blown polyester, meaning that they have a high water retention ability, approaching or equalling PVA, but with visible pores and more flexibility of applications.
- More information on this topic is available at [ Wikipedia:Sponge (material) ]